On 29.09.20 14:30, Michal Hocko wrote: > From: Michal Hocko <mhocko@xxxxxxxx> > > There is a general understanding that GFP_ATOMIC/GFP_NOWAIT are > to be used from atomic contexts. E.g. from within a spin lock or from > the IRQ context. This is correct but there are some atomic contexts > where the above doesn't hold. One of them would be an NMI context. > Page allocator has never supported that and the general fear of this > context didn't let anybody to actually even try to use the allocator > there. Good, but let's be more specific about that. > > Another such a context, and that is where people seem to be more daring, > is raw_spin_lock. Mostly because it simply resembles regular spin lock > which is supported by the allocator and there is not any implementation > difference with !RT kernels in the first place. Be explicit that such > a context is not supported by the allocator. The underlying reason is > that zone->lock would have to become raw_spin_lock as well and that has > turned out to be a problem for RT > (http://lkml.kernel.org/r/87mu305c1w.fsf@xxxxxxxxxxxxxxxxxxxxxxx). Interesting Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> -- Thanks, David / dhildenb
